Hi,
Bought from ebay (another) blown up 3048 in box. Did not expect much from it, but sometimes I get myself these kind of models just to see how difficult may be to convert them in perfect runners again.
I tested it when it arrived. Other than its poor appearance, as expected, it had a very rough running (not a single drop of oil or grease on it in many years), but it also shown some kind of jerky running, slow down-accelerate, slow down-accelerate...it seemed to have some mechanical issue/s. As I was quite busy at the time, I left the poor thing somewhere. At least, it could move by itself!
Today I've found some time and I've checked it. After removing the shell, what I see makes me think that somebody has got himself a couple of these 3048s, has dissassembled them and then:
1-re-assembled one with the best parts of both. (this one is not the one I've received).
2-re-assembled another with the worst parts of both (and yes, this is the one I've got).
I've dissassembled the motor, the reverse unit and the bulb holder and have sprayed some degreasing fluid on it, to check if the "hard point" went away. No success.
So I've started dissassembling it completely.
That's what I've got:
A bent cabin roof in a dirty, rusty and peeled off early body (which also has some bent handrails :D ):

Haven't tested the smoke unit yet but having seen the rest of the loco, don't expect it can work:

Very nice slider:

Missing oil foam in chassis and in motor cover:


I guess these wheels have many km on them...the yellowish appearance is wear:

Well, after complete dissassembly and some cleaning, what I had was this:


Fortunately these ones are quite well engineered...there are sleeves on the axles, and regardless of use, axles and metal gears were in quite good condition. Intermediate gears are made from nylon, what seems quite strange. I've overhauled another 3048 which was a later model and that one had metal intermediate gears.
A close looking to the nylon gears showed the problem:

(notice two bent teeth on the first gear)
So now there's some solution to be found to be explained...tomorrow.